Momentary viewing apparatus



Nov. 11, 1958 A. c. ALLEN MOMENTARY VIEWING APPARATUS Filed May 17, 1957 INVENTOR.

MOMENTARY VIEWING APPARATUS Arthur C. A llen,v Chicago, Ill., assignor to Stewart-Warner Corporatlon,.Chlcago, Ill., a corporation of Virginia Application May 17, 1957Serial No. 659,937

Claims. (CL '7S-M466)v rl"hepresent invention relates to devices for momentanly viewing a moving object intermittently to correlate instantaneous positions of the object with a reference sysem. Apparatus of this character'is used to locate unbalance in vehicle support wheels while the wheels remain mounted on coacting Vehicle axle structure. The wheel to bechecked for unbalance is temporarily suspended by its axle structure and rotated at a rather high speedin a manner thatallows any signiiicant unbalanced mass inthe wheelto vibrate the wheel and its adjacent axle structure. The unbalance locating apparatus senses these vibrations and provides momentary views of the wheel individually synchronized with a predetermined phase of the successive'vibratory cycles.

Ordinarily each momentary view of thewheel is provided by a rash of artificial light yhavingA an effective intensity-on the wheel greater than the intensity of the con tinuous ambient light. Becausef of the relatively high light intensity` ofthe ashes and the rapid succession of the iiiashe's,'thebintermittent views of the wheel thus pro vided' are perceived as Va continuous dominant viewV of the instantaneous position of the wheel as related to its'.vi bratory movementrinduced by unbalanced mass 'in the wheel.' f v; While the view providedbythe light ilashes c-antbe verydistinct in. ambientlightthat is somewhat subdued,

i-trbecomes less dominant and therefore less distinct in brighter light. In bright'- sunlight the dominance and h'ence, the distinctiveness o f the view provided'by the flashinglight may not be satisfactory.

One object of the invention is to provide, for use in either very brightV or 'subdued ambient light, intermittent viewing'apparatus having an improved construction which responds to vibratory movementV of a rotating vehicle sup.` port wheelwor the like to afford momentaryviews of' the wheel Vprecisely phased with itslvibratory motion` and having;L great clarity andi distinctiveness even in the brightest aimlight;A w i A. more specicobject of the invention is' toA provide, for viewing the instantaneous position of' ac'cntinuously Other objects and advantages will become apparent from the following description of the exemplary embodiment of the invention illustrated in the drawings, in which:

Figurel is a partially sectioned and partially schematic side View showing apparatus embodying the invention applied to locate unbalance in a suspended vehicle support wheel; Fig. 2 is a vertical sectional view taken along the line 2;;2 of Fig. 1; and

Fig. 3 is a fragmentary sectional View on an enlarged scale taken along the line 3 3 of Fig. 2.

Designed -for use in locating unbalance in a continuously lighted vehicle support wheel 10, Fig. l, the exemplary embodiment of the invention eclipses a direct view of the wheel andV responds instantaneously to movement of the Wheel through an exact predetermined phase of a 'vibratory `-cycle to make the normally eclipsed view of the wheel momentarily visible by the ambient light 'continuouslyreected vfrom the Wheel. During an unbalance determining operation, the wheel 10 is rotated at a rather highv speed while mounted in a normal manner on its vehicle axle structurev 12, which is temporarily elevated to suspend the wheel above the roadway 14. Means suitable for spinningv the wheel 10 and means `for sustaining the axle structure 12 in an elevated position in a manner Which permits vibration of the axle structure by unbalanced mass in the rotating wheel are well known in the art andl need not be specifically described here.

Vibratory movement of the wheel 10 is sensed by an electrical pickup 16 connected to the axle structure 12 and resting, in this instance, on the roadway 14. The construction of the pickup 16 may be similar to that shown` in U. S. Patent No. 2,656,713 issued October 27, 1953, to Arthur C. Allen, or that shown in the patent application of Paul C. Hosking, Serial No. 623,650, tiled November 2l, 1956. In operation, the pickup 16 re-` Sponds to vibratory movement of the axle structure 12 to closean electrical connection between two electrical leads '18 as the axle structure moves through the center ofl the path of vibratory motion sensed by the pickup.

The two leads 18 extend from the pickupV 16 to elec'- trical signal generating means 20, which is designed to discharge an electrical impulse instantaneously in response to completion of an electrical circuit through the leads 18 and the pickup 16. The desired electrical impulse is obtained by firing a strobotron 22 forming a part of the signal generating means 26. The structure of the signal generating means 20 which res the strobotro'nv 22 in response to operation of the pickup 16v to make. an electrical connection between the leads 18 is'shown vin i" the previously mentioned Allen Patent No. 2,656,713' to lighted moving: object?, van improved! viewer -whichlnori mally eclipsesY a direct View of the object and responds substantially` instantaneously to a single electricalyimp'ulse tol render the normally..eclipsedv viewmom'entarily visible bythefcontinuousambient light on the object.

f Another object `is to providezran` intermittent 'viewergeas'l A recited-in:` the previous object, whichf is 'sofconstructed that the operation of the viewer tri-render a normally eclipsed" view momentarily visiblesubstantially instantaneously in response tov av singlev electrical impulse is not affected by.Y

which reference canbe made for a detailed description', Inv the'pa-tent, the strobotronltl corresponds to the strob`= otr`o1if22` ot the present application. Y, d v I Y, i Whereas the strobotron of the Allen patent justreferred to fsferves4 as a source ofHstro-boscopic light for viewinga rotating'wheel, the stroootron 22 of the signal 'generating apparatus 20-isiired primarily to obtain an electrical inipulse, which is used to make a normally eclipsed View of therotatingwheel 10 momentarily visible by the continuousambient lighton the wheel.

j The anode 24 of the strobotron 22 is grounded through two electrical' leads Z6, 23, which connect respectively toV the anode itself and to a suitable ground connection on The leads26, 28 ex,

rear or'viewing end 40 of the barrel 34 is shaped to t comfortably around the eye of the user, where it may be conveniently supported by a pistol grip handle 42 extending laterally from the rear end of the barrel.` Y

The objective end 38 together with the viewing end 40 of the barrel 34 dene a line of sight through the barrel between the viewing end'40 and a limited field of view'in front of the barrel. This line of sight is normally eclipsed by a low inertia View eclipsing element 44 disposed within the barrel 34 a considerable distance from its viewing end 40. For convenience in description the barrel 34 will be considered as being located in a generallyhorizontal position with the handle 42 extending downwardly i from the barrel. l A

The view eclipsing element 44 comprises a very` thin cylindrical shell 46 formed preferablyfrom a light weight material, such as aluminum, and having a diameter and an axial length approximately equal to each other. The shell 46 is placed in the barrel 34 about two-thirds of the way from the viewing end 40 toward the objective end 38. The axis of the shell extends horizontallyacross the barrel 34 in generally perpendicular relation to the line of sight Vthrough the barrel. As shown in Fig. 2, the barrel 34 is squared transversely and dimensioned to closely' embrace opposite ends of the shell 46 and'substantially register tangentially with upper and lower cylindrical portions of the shell.

The cylindrical shell 46 is supported for pivotal movement around its own axis by a pair of web's 48 in opposite ends of the shell, which are pivotally journaled at 49 on the upper ends of two support ears 5t) of a support cage 52 forming a part of the body structure 32. The cage 52 extends down through an opening 54 in the bottom'of the barrel 34 and into a hollow protuberance 56 projecting downwardly from the marginal edge of the barrel opening 54. The cage 52 is secured to the protuberance 56 by screws 58.

The shell 46 is strongly biased Vrotatably about its pivotal axis by a tension spring 60 connected between the lower end of the cage 52 and one end of a straight actuator blade 62 extending tangentially from the lower portion of the shell to which Vthe medial portion of the blade is securely attached. AsV shown, the spring 60 is connected to the end of the blade 62, which projects toward the handle 42, thus biasing the shell 46 in the clockwise direction, as viewed in Figs. l and 3.

The upper face of the opposite end of the blade 62 very small angle from the previously mentioned view eclipsing position of the shell.

The cylindrical half-section 74 of the shell 46 nearer the objective end 36 of the barrel 34 is apertured by a circumferential series of narrow longitudinal slots 76 parallel to the axis of the shell, Figs. 2 and 3. The series of slots 76 is bounded by unsevered portions of the shell 46, which include a series of opaque bars 78 intervening between and separating the slots.

The cylindrical half-section 80 of the shell 46 nearer the viewing end of the barrel 34 is apertured to form a circumferential series of narrow slots 82 separated by an intervening series of opaque bars 84, all substantially parallel to the axis of the shell 46.

The series of slots 76 and bars 78 in the forward or objective portion of the shell 46 and the series of slots 82 and bars 84 in the rear or viewing portion of the shell are oriented and dimensioned in relation to each other so that the rearwardly extending shadows 86 of the forward bars 78 and adjacent unsevered structure of the forward portion 74 of the shell completely lill and block the view through the opposing slots 82 Vat Vthe rear, when the shell 46 is in its normal view eclipsing position shown in Fig. 3. Put another way, the unsevered structure (including the bars 84) of the rear portion 80 of the shell 46 block the shafts of light S8 extending rearwardly from the forward slots 7 6, when the shell is in its view eclipsing position.

fThus movement of the shell 46 into its view eclipsing position, Fig. 3, brings each of the slots 76, 82 into registry, transverse to the line of sight through the barrel, with an opposing opaque portion of the shell. The width of the bars 78, 84 is at least equal to that of the respective opposing slots 84, 76.

The magnetic rotation of the shell 46 to the viewing position previouslymentioned is just sucient to bring the forward slots 76 and the rearward slots 82 into registry with respectto the line of sight through -the barrel 34. This permits the shafts of light 88 to continue from the forward slots 76 on through the rearward slots 82,

thus making the normally eclipsed view momentarily visible.

The moving parts of the viewer 30 are limited tothe Y pivotal eclipsing element 44 and the connected end of the forms an abutment which engages an overlying abutment 64, the actuator 62 is generally parallel tortherlongitudinal axis of the barrel 34, Fig. 3.

The shell 46 is rotatably snapped in the counterclockwise direction, Fig. 1, against the action of the spring 60 by a low impedance electromagnet 66, which attracts the end of the actuator blade 62 opposite from the spring. The actuator blade 62 is formed from magnetic material. As shown, the electromagnet 66 includes a magnetic core 68 attached to the lower end of the cage 52 and extending upwardly into underlying relation to the end of the actuator 62 projecting under the abutment 64. It is noteworthy that the lower end of the cage 52, which serves as a support for the electromagnet core 68 and an anchor for the spring 60, is also constructed of magnetic material. A low impedance coil 70 encircles the core 68 and is connected at opposite ends to the signal generator leads 26, 28, which extend upwardly through a cap 72 on the lower end of the protuberance 56.

The upper end of the electromagnetic core 68 and the underside of the adjacent end of the actuator 62 respectively constitute a pair of abutments which engage to terminate electromagnetic, counterclockwise rotation of the shell 46 in a viewing position displaced rotatably only a spring 60. The eclipsing element 44 is normally at rest in its view eclipsing position. Because of the low rotational inertia of the eclipsing element 44, the very small angle between its eclipsing position and its viewing position, the low impedance of the electromagnet 66, and a relatively high capacity of the electromagnet 66 to apply torque to the eclipsing element, the viewer 30, in effect, snaps the eclipsing element 44 into viewing position instantly in response to a single magnetic impulse supplied from the generating means 20 through the leads 26, 28. The spring 60 is equally effective in shaping the eclipsing element 44 back to its stationary, view eclipsing position, where the kinetic energy and momentum gained by the element in making the normally eclipsed view momentarily visible is instantly dissipated.

Since the eclipsing element 44 is at rest both at the beginning and at the end of each Voperating cycle, it follows that the response of the viewer 30 to the individual electrical impulses supplied from the signal generator 20 is not affected by the changes inthe rate at which the im ulsesfollow each other, with the possible exception of control pulse rates which are close' to the natural vibrating frequency of the view eclipsing structure.

However, this possible exception is of no practical significance, since the rate at which control Vpulses are supplied in response to vibrations of a vehicle support wheel 10 during an Vunbalance determining operation are far outside the resonant frequency of the eclipsing structure.

The location of unbalance in the wheel 10 is determined in a conventional manner from the observed-position of an indicator 90 on the wheel as revealed by the momentary views provided by the viewer 30.

Since the wheel is viewed by the continuous ambient lightv on the wheel, it follows that increases in intensity of this ambient light improve rather than detract from the distinctivenessand clarity of the momentary views `provided through the viewer 30. Hence, the apparatus is especially well suited for use in bright sunlight. While I have shown a preferred embodiment of my invention, it will be apparent that numerous variations and modifications thereof may be made without departing from the underlying principles and scope of the invention. I therefore desire, by the following claims, to include all such variations and modifications by which substantially the results of my invention may be obtained through the use of substantially the same or equivalent means.'

I claim:

1. For normally eclipsing light continuously reflected from a view of limited scope and making the view momentarily visible only once in response to a single electrical impulse, a momentary viewer comprising, in combination, body means including a hollow barrel having 'an objective end and a viewing end defining a line of sight through the barrel, a rst wall element extending transversely across the interior of said barrel a substantial distance from the viewing end thereof, a second wall element extending transversely across the interior of said barrel between said first wall element and the viewing end of the barrel, a magnetic actuator on one of said wall elements, a spring interconnected between said body means and said o-ne Wall element to movethe latter with respect to the other wall element in transverse relation to said-line of sight to a view eclipsing position, an electromagnet mounted on said body means adjacent said magnetic actuator to attract the latter against the action of said spring to move said one wall element to a viewing positiondisplaced with respect to said other wall element transversely in relation to said line of sight, each of said wall elements being formed to define therein a pattern of apertures similar to the pattern of apertures in the other wall element and to define between the apertures opaque structure having dimensions transverse to said line of sight which are larger than similar dimensions of corresponding apertures in the other wall element, said apertures being dimensioned and located in the respective Wall elements to effect when said one wall element is in said viewing position a registration transverse to said line of sight of the apertures in each wall element with the apertures in the other wall element, and the spacing between apertures in each wall element being at least equal to the displacement of said one wall element relative to the other wall element in moving between said view eclipsing position and said viewing position.

2. For normally eclipsing light reflected from a continuously lighted view of limited scope and making the View momentarily visible only once in response to a single electrical impulse, a momentary viewer comprising, in combination, body means including an elongated barrel having an objective end and a viewing end defining a line of sight through the barrel, a View eclipsing element including a thin cylindrical shell extending transversely across the interior of said barrel a substantial distance from the viewing end thereof, means on said body means supporting said eclipsing element for pivotal movement about the axis of said shell, a magnetic actuator integral with said shell and forming a part of said view eclipsing element, a spring connected between said body means and said eclipsing element to yieldably pivot the latter in one direction about said axis of pivotal movement, said body means and said eclipsing element respectively defining an opposing pair of abutment surfaces for terminating pivotal movement of said eclipsing element in said first direction in a predetermined view eclipsing position, an electromagnet on said body means positioned adjacent said magnetic actuator to magnetically attract the latter in a direction to pivot said eclipsing element against said spring to a viewing position displaced a small angle from said view eclipsing position thereof, said shell including two portions thereof facing respectively toward the viewing end and the objective end of said barreLeach of said shell portionsy being formed to define a series of slots generally parallel to the pivotal axis of said eclipsing element and an intervening series of opaque bars separating the slots andrhaving a width at least equal to that of corresponding slots in the other shell portion, and said slots being dimensioned and located on said shell to effect when said eclipsing element is in said viewing position a registration transverse to said line of sight of the series of slots in one of said shell portions with the series of slots in the other shell portion and to effect when said eclipsing element is in said eclipsing position a registration transverseto said lineof sight of slots in one of said shell portions with bars in the other shell portion.

3. For normally eclipsing light reflected from a continuously lighted view of limited scope and making the view momentarily visible only once in response to a single electrical impulse, a momentary viewer comprising, in combination, body means including an elongated barrel having anobjective end and a viewing end defining a line of sight through the barrel, a view eclipsing element including a thin view eclipsing shell traversing the interior of said barrel a substantial distance from the viewing end thereof, pivot means supporting said shell on said body means for pivotal movement about an axis generally perpendicular to said line of sight, said view eclipsing element including as a portion thereof a small mass of magnetic material spaced from said axis and convstituting a magnetic actuator integral ywith said shell, a spring connected between said body means and said eclipsing element to yieldably pivot the latter rotatably in'a first direction about said axis, said body means including an electromagnet positioned adjacent said magnetic' actuator to attract the latterk in a direction which pivots said eclipsing element about said axis in a second direction opposite said first direction, said body means and said eclipsing element respectively defining a first pair of opposing abutments positioned to terminate pivotal movement of said eclipsing element in said first direction in a predetermined view eclipsing position, said body means and said eclipsing element respectively defining a second pair of opposing abutments positioned to terminate pivotal movement of said eclipsing element in said second direction in a viewing position displaced rotatably from said eclipsing position by only a very small angle, said shell including two wall portions spaced from each other along said line of sight and traversing the interior of said barrel, each of said wall portions being apertured to dene a series of slots generally parallel to said shell axis and separated by an intervening series of opaque bars having a width at least equal to that of corresponding slots in the other wall portion, and said slots being dimensioned and located in said shell to effect when said eclipsing element is in said viewing position a registration transverse to said line of sight of the series of slots in one of said wall portions with the series of slots in the other wall portion and to effect when said eclipsing element is in said eclipsing position a registration transverse to said line of sight of slots with bars in the opposing wall portion of said shell.

4. Apparatus for locating unbalance in rotating vehicle support wheels or the like, comprising, in combination, an electrical pickup sensitive to mechanical vibrations, an electrical impulse generator connected to said pickup to produce electrical impulses in response to vibratory actuation of said pickup, an electromagnet connected to said impulse generator for momentary energization by electrical impulses produced by said generator, a hollow barrel having a viewing end and an objective end; a pivotal View eclipsing element including a thin, view eclipsing shell traversing the interior of said barrel; means supporting said shell for pivotal movement about an axis generally perpendicular to the longitudinal axis of said barrel, said view eclipsing element including as a portion thereof a small mass of magnetic material spaced from the' pivotalaxis of said shell and constituting a magnetic actuator integral with the shell, a spring connected to said eclipsing element to yieldably pivot the latter rotatably in a iirst direction about said pivotal axis thereof, abutment means connected with said barrel and coacting with said eclipsing element to terminate pivotal movement of the latter .in said first direction in a predetermined view eclipsing position, said electromagnet having a position adjacent said magnetic actuator to attract the latter to pivot said eclipsing element against said spring to a viewing position displaced a small angle from said eclipsing position, said shell including two barrel traversing portions spaced from each other along the longitudinal axis of Ysaid barrel, each of said shell portions being formed to define a circumferential series of apertures separated by intact shell structure, and said apertures on both shell portions being dimensioned and located on the shell to effect when said eclipsing element is in said viewing position a registration transverse to the longitudinal aXis of said barrel of the apertures in one of said shell portions with the apertures in the other shell portion and to effect when said eclipsing element is in said eclipsing position a registration transverse to said longitudinal barrel axis of the apertures in one of said shell portions with the Y intact shell structure of the other shell portion, each of said apertures being somewhat smaller than corresponding intact shell structure of the opposing shell portion.

5. Apparatus for locating unbalance, in rotating vehicle support wheels or the like, comprising, in combination, body means including a hollow barrel having an objective end and a viewing end defininga line of sight through the barrel, a first masking element extending transversely across the interior of said barrel a substantial distance from said viewing end thereof, a second masking element extending transversely across the interior of said barrel Ybetween s'aid'iirst masking element and said viewing end of the barrel, a magnetic actuator on one of said masking elementsa spring interconnected between said body means and said one masking element to move the latter relative to the other masking element in a direction transverse to said line of sight to a normal View eclipsing position, an electromagnet mounted on said body means adjacent said actuator to attract the latter against the action of said spring to move said one masking element relative to the other masking element toa viewing position displaced from said eclipsing position transversely with respect to said line of sight, each of said masking elements being formed to deine therein a pattern of transparent areas similar to the pattern of transparent areas defined in the other masking element and to dene between the transparent areas in the masking element opaque structure having dimensions transverse to said line of sight which are at leastequal to similar dimensions of adjacent transparentareas in the other masking element, an electrical impulse generator connected to said electromagnet to supply electrical impulses thereto, and an electrical pickup connected to said impulse generator to trigger operation of the latter to momentarily energize said electromagnet.

References Cited in the file of this patent UNITED STATES PATENTS Y Pheips oct. 25, 1955 

